JPH02145876U - - Google Patents

Description

[Brief explanation of drawings]

1 and 7 are block diagrams showing embodiments of a switching circuit of a signal processing section in a dual-purpose receiver for multiple TV broadcasts using different standard systems according to the present invention, FIGS. 2 and 3, and FIG. 5, respectively. The figure is an explanatory diagram of the frequency discrimination characteristic curve (S curve) and input/output characteristics of the frequency discriminator, Figure 4 is a block diagram showing a specific example of the configuration of the voltage comparison circuit and switch control circuit, and Figure 6 is a diagram of the switch control circuit. Diagram for explaining the operation of the control circuit, No. 8
16 to 16 are examples of transmitting and receiving characteristic curves for a plurality of TV broadcasts using different standard systems, FIG. 17 is a connection diagram of a configuration example of a phase compensation circuit, and FIG. 18 is a block diagram of a conventional example. 1... Receiving antenna, 2... Tuner, 3-5
...Has the passband characteristics and group delay characteristics required by a receiver when receiving broadcast waves according to the PAL (B/G) system, the PAL (I) system, and the PAL (D/K) system. Each bandpass filter, 6... Video intermediate frequency detection stage, 7...
...Audio intermediate frequency amplification stage, 8...Audio FM detection circuit, 9...Low pass filter, 10...Voltage comparison circuit, 11...Switch control circuit, SW1 to SW6...
...Switch, 12...The pass band required for good reception of the standard TV broadcast that has the widest video signal band among the multiple TV broadcasts of different standard systems that are targeted for reception. A bandpass filter having a characteristic and a group delay characteristic, 13
~15... A plurality of phase compensation circuits for providing video information with group delay characteristics required for good reception of TV broadcasts of individual standard formats in a plurality of TV broadcasts using different standard formats, 19
, 22... Voltage comparator, 17, 18, 20, 21
... Resistor, 23 ... NAND circuit, 24 ... Input terminal, 25 ... Output terminal, 26, 28, 29, 31
, 32, R1, R2...Resistance, 27, 30, 33
...Transistor, C1, C2...Capacitor,
L1, L2...Coil.

Claims (1)

[Claims for Utility Model Registration] 1. Provides passband characteristics and group delay characteristics that are required for good reception of TV broadcasts of individual standard formats among multiple TV broadcasts using different standard formats. A plurality of band-pass filters are provided before the video intermediate frequency detection stage, and one of the plurality of band-pass filters described above is used to select a filter that is necessary when receiving a TV broadcast of a specific standard format. A changeover switch that selectively connects a band-pass filter to a video information transmission system, and a frequency difference between a video carrier frequency and an audio carrier frequency in multiple TV broadcasts using different standard systems. Voltage generating means for generating different voltages, and comparing the voltages generated by the voltage generating means with a reference voltage to generate a switch switching control signal, which is required when receiving a TV broadcast that is being received. A switching circuit of a signal processing section in a multi-purpose receiver for a plurality of TV broadcasts of different standard formats, comprising means for switching and selecting a bandpass filter by a switch. 2 TV with the standard format that has the widest video signal band among multiple TV broadcasts using different standard formats
A bandpass filter having passband characteristics and group delay characteristics required for good reception of broadcasting is provided before the video intermediate frequency detection stage. In the transmission system of the video information following the wave stage, the TV of each standard format in multiple TV broadcasts with different standard formats.
A plurality of phase compensation circuits are provided for giving video information the group delay characteristics required for good reception of broadcasting, and furthermore, a TV of a specific standard system being received from among the plurality of phase compensation circuits is provided. a changeover switch that selectively connects a phase compensation circuit required during broadcast reception to a video information transmission system;
Voltage generation means for generating different voltages corresponding to the frequency difference between the video carrier frequency and the audio carrier frequency in a plurality of TV broadcasts using different standard systems, and a voltage generated from the voltage generation means described above as a reference. means for generating a switch switching control signal by comparing the voltage with the voltage of the current TV broadcast, and for causing the switch to switch and select the phase compensation circuit required when receiving the TV broadcast being received. A switching circuit for a signal processing section in a dual-purpose TV broadcasting receiver.